In general, a driving assistance apparatus that assists in driving a vehicle uses an on-vehicle camera and a navigation system to obtain traffic information on a street crossing, a stop position, a curve, and approach of vehicles ahead, which require control of deceleration of the vehicle. Based on the thus obtained traffic information in the vicinity of vehicles, driving assistance such as guidance for deceleration by sound or deceleration assistance by providing braking force in a semi-compulsory manner is performed.
Conventionally, as an example of the driving assistance apparatus, there is known, for example, as disclosed in Patent Document 1, an apparatus that assists in controlling the distance between a vehicle that is an assistance target and a preceding vehicle, which travels ahead of the vehicle in an advancing direction. This apparatus recognizes, upon performance of driving assistance, the presence of the preceding vehicle by detecting a relative position and a relative speed of an object that is present ahead of the assistance target vehicle in the advancing direction. Next, upon detection of the preceding vehicle, the control of a vehicle-to-vehicle distance, by which the preceding vehicle is followed by the host vehicle, is performed. In controlling the vehicle-to-vehicle distance, for example, when the distance between the assistance target vehicle and a preceding vehicle, becomes greater than or equal to a predetermined distance, the control for accelerating the assistance target vehicle is performed. Further, when no preceding vehicle is detected, control of the speed of the vehicle, a so-called cruise control, which controls the speed of the assistance target vehicle at a set speed, is performed. In this cruise control, when the traveling speed of the assistance target vehicle becomes lower than the set speed, the vehicle is controlled to accelerate to the set speed.